Art of combustion



Feb. 15,. 1927.

C. SCHWARTZ ART OF COMBUSTION Filed March 11, 1924 2 Sheets-Sheet 1INVEA ITO R ATTORNFV(5 Feb. 15, 1927.

C. SCHWARTZ ART OF COMBUSTION INVENTOR 1924 2 Sheets-Sheet 2 ATTORNEYSWI 7775 $5 M W Patented Feb. 15, 1927.

UNITED STATES PATENT-OFFICE.

CARL SCHWARTZ, OF NEW ROCHELLE, NEW'YORK, AS SIGNOR TO INTERNATIONALCOMBUSTION ENGINEERING CORPORATION, CORPORATION OF DELAWARE.

I ART OF COMBUSTION.

Application filed March 11, 1924. Serial No. 698,409.

This invention relates to the art of 'combustion and the art ofgenerating steam, and is especially useful in the burning of fuel insuspension, such as pulverized coal.

' In so far as the burning of the fuel is concerned, my inventioncontemplates the more effective and efiicient combustion there of and ina furnace requiring minimum ground area. A further object inthis respect is to practically burn the fuel with higher temperatures, inshorter. time and less flame travel, if desired. Still another objecthas to do with the accomplishment of the foregoing without rapiddestruction of the brick work and without forcible im pingement of theflames or refuse leaving the flame thereon.

With respect to the boiler, the invention contemplates an associationthereof with the combustion chamber such that minimum floor space istaken up, it being much less expensive to take up space vertically thanhorizontally. Another object of'the invention is to arrange the boilerso that the heat developed by the furnace may be most elfectivelyapplied and the work of the boiler enhanced; while at the same time thestructure of the installation, considered as a whole, is simplified. Astill further object has to do 3 with the reduction of dead spaces inthe boilerto a negligible factor. Another obzxect has to do with anarrangement of the oiler into units stacked, so to speak, one

' over another, with circulating connections 85 such that thisarrangement may be practically followed.

Thus the invention broadly eontem lates an inc ease in combined furnaceand oiler efiicien'ep. 40 The oregoing, together with such otherolg'ects' as may hereinafter appear or are inci cut to my invention, Iobtain by means of a construction illustrated in preferred form in theaccompanying drawings, where- .m:

Fig. 1 is a vertical cross section through one form of furnace embodyingmy invention;

Fig. 2 is a similar section showing a modiso fication;

Fig. 3 is a fragmentary section illustrating a modification of a detailof the invention;

Fig. 4 is a vertical section through a furnace and boiler embodying theinvention;

Fig. '5 is a section taken on the line 5 5 tion of the boiler; and Fig.7 is a, sectional detail of another modification.

Referring now to Fig. 1,I have therein shown a vertical combustionchamber A, of circular cross section preferably, and having an outlet- 7for the escape of the gaseous products of combustion, under theinfluence of the draft, at the top. The lower part of the chamber ispreferably hopper shaped with a gate controlled outlet 8. The chambermay, if desired, have a smaller horizontal dimension than customary andthe height is such that combustion is completed before the flames reachany evaporating surfaces over the outlet. The height, relativelyconsidered, may also be less than usual, i. e. the flame path may be.shorter. This may be brought about by the manner of admission andburning of the fuel now to be described.

The fuel, in suspension, is admitted through a plurality of burners 9,in opposing and impinging substantially horizontal streams, at a pointwell above the bottom or floor of the chamber. Air may be supplied atthe burners, as by induction, as illustrated. The velocity of the fuelstreams is such that the fuel is effectively carried in, without,however, producing a surging so violentas to'forcibl carry-the flames tothe walls or to cause t e space in the bottom to be fully occupied byflame. On entering, the streams promptly ignite, the lighter particlesrismg underthe draft and the 'cores impinging, producing a centraleddying securing proper admixture to further combustion. Here, again,lighter particles, exploded particles, and gases liberated rise underthe draft, and heavier particles of fuel may fall. In falling, they meetwith or pass into an underlying strata of air supplied thrpugh amultilicity of inlets 10 in the walls of the chamber. They are thereexploded and burn, becoming practically instantaneously broken up andgasified, whereupon the draft be-j comes efi'ective thereon and theymove upopenings 11, preferably damper controlled if they be made ofsubstantial size. The rising stream thus progressively meets fresh air,

drawn in by induction and at right angles,

whereby a slight peripheral eddying is set:- up furthering combustion.The film of air also protects the wall against erosion; lt practicallythe greater portion of the air for combustion be admitted with the coal,then the size of the inlets 10 and 11 will be cut down so as to minimizethe amount of excess air while still preserving the protective features.Under such conditions, the flame will be short, bright and extremelyhot. If less air be admitted to the-burners, the size of the inlets mabe well increased, whereupon the flame wil be longer and less hot.

In any event the bottom of the chamber should be cooled to prevent thecoalescence of the precipitating refuse into liquid slag, if the bottomof the chamber wall is made. of refractory material. In the arrangementshown, the air admitted through the inlets 10 serves to cool the ash andto perform the other functions mentioned. The deposit is thereforereadily removable.

In the arrangement of Fig. 2, the chamber is bellied out in the regionwhere the fuel is admitted to make it possible to reduce the extent ofeddying or to avoid the detrimental effects ofextensive cddying,-and tohold up the flame higher from the bottom. It also afi'ords anopportunity for a greater progress of combustion before impingementoccurs.

In the arrangement ofFig. 3, the air is admitted in such manner as tosweep the wall circumferentiall As to the combustion chamber of Figs. 4,5 and 6, the wall is hollow and air may be introduced into the spaceunder pressure through a pipe or pipes 12, flowing into the combustionspace in jets through a multiplicity of relatively small or tin openings13, functioning, in essentials, as t ose before described. Thepreheating of the air is advantageous as the furnace temperatures arenot lowered as greatly. The walls are also additionally protected by theabsorption by the air of someheat therefrom. The fuel is admitted in alurality of streams between which a plurality of streams of air areadmitted, as at 14, all streams converging. Intimate'admixture is thussecured, less-air need be supplied through the chamber wall, and theflame may be shorter and hotter.

\Vith reference to the boiler, I have proceeded upon the assumption,using a horizontal boiler for illustration, that the first pass is theboiler proper, where about of thework of evaporation is performed, andthat the subsequent s are practically economizer sections, andicapped bydead spaces. About 60% of the work of the first pass is performed in thelowermost tubes.

1 therefore propose (to divide the boiler into short sections or units,stacking them over the outlet 7, one above the other. The lower unit 15does the work of the first pass, and the higher units 16 of Fig. 4 and16 and 17 of Fig. 6 do the work of the other economizer passes. Thegaseous products, however, rise successively through the units and aremore effective] y applied. The dead space is ne ligible, if existent atall. Each unit is simp e. The lower unit may have larger tubes than theothers and the space around the tubes may be less in successive units orprogressively less in a unit, to compensate for the contraction of thegases and to provide for maximum heat transfer. Less draft. may be usedas there is no reversal of the gases.

Because of different conditions as to circulation I prefer to have eachunit connected to have self confined or local circulation, in order toavoid difficulties which might otherwise be encountered, In the arranement of Fi 4, I connect the low point of t e unit 15 wit the drum 18 bymeans of a. large pipe or pipes 19, and the high point by means of t epipe or pipes 20, also large. The unit 16 is similarly connected withits drum 21 by pipes 22 and 23. The setting is simple.

In the arrangement of Fig. 6 substantially the same arrangement isfollowed for each unit.

Referring to Fig. 7, the space in the hollow wall is divided intocompartments to each of which air is supplied through the casing 24 bythe damper controlled inlets 25. By this arran ement regulated controlof the air supplieil into different areasof the chamber may be obtainedto the end of securing nailrimum efficiency in the burning of the Iclaim:

1. In the art of combustion, the method of burnin pulverized fuel in asubstantially cylindrical vertical boiler furnace having an outlet atthe top, which consists in in ecting the fuel in suspension in aplurality of su s tantially horizontal converging streams into the lowerpart of the furnace chamber, in i iting the streams of fuel, inadmitting com ustion air below the convergin streams, in drawing theburning fuel an air upwardly in a, column toward the outlet under theinfluence of the draft, and in admitting additional air at amultiplicity of points around the periphery of the column substantial]throughoutits length sufficient to protect the wall of the chamber fromforcible impingement of the flame and to burn the fuel completely beforesaid column reaches the outle 2. A boiler furnace for the combustion ofpulverized fuel, comprising, in combination, a substantially cylindricalvertical combustion chamber, a plurality of peripherally spaced andsubstantially horizontally dis posed fuel and air injectmg nozzles nearthe ottom of said chamber,and a multiplicity of peripherally disposedair inlets throughout the greater part-of the height of the chamber.

3. A boiler furnace for the combustion of a substantially cylindricalvertical combustion chamber, a plurality of peripherally spaced andsubstantially horizontally disposed fuel and air injecting nozzles near"the bottom of said chamber, a multiplicity of peripherally disposed airinlets throughout the greater part of the height of the 1- path oftravel for the combustion stream 2 from the point of entry.

In testimony whereof, I have hereunto signed my name. 1

' CARL SCHWARTZ.

